1. Field of the Invention
This invention relates to a magnetic recording and/or reproducing apparatus, and more particularly to an improvement of the recording and reproducing of a high quality audio signal using a digital audio tape recorder.
2. Description of the Related Art
In the conventional digital audio tape recorder, helical recording tracks are formed along a magnetic tape so that a high-quality digital audio signal is recorded and reproduced.
In the digital audio tape recorder 1 shown in FIG. 1, when a tape cassette 2 is loaded, a magnetic tape 6 is taken up from the tape cassette 2 by moving guide posts 4 and is then wrapped around a rotary drum 8.
Further in the digital tape recorder 1, when a user manipulates switches to set up a recording mode or a reproducing mode, the rotary drum 8 is rotatably driven at a predetermined speed, and a capstan motor is driven to run the magnetic tape 6 at a predetermined running speed.
When the user selects the recording mode in the digital audio tape recorder 1a, two-channel 16-bit digital audio signal D1 is input to a digital signal processing circuit 10, which executes dividing the digital audio signals into blocks in synchronization with the rotating period of the rotary drum 8.
After the audio data of which the audio signal arranged in blocks is interleaved in units of blocks, the digital signal processing circuit 10 generates an error correcting code, and outputs the error correcting code with the interleaved audio data as well as sub data and the like to an 8-10 modulating circuit 12.
The 8-10 modulating circuit 12 performs 8-10 modulation of the output data sequentially provided from the digital signal processing circuit 10 to convert it into recording data which are then fed to a magnetic head mounted on the rotary drum 8 via a recording amplifying circuit 14.
In the digital audio tape recorder 1, a positive azimuth angle recording track and a negative azimuth angle recording track in pairs are sequentially formed, and audio data are recorded onto the pair of recording tracks in block-by-block units. Thereby, the digital audio tape recorder records sequentially the digital audio signal D1 according to the standardized format.
In the digital audio tape recorder 1, for example, as shown in FIGS. 2A and 2B, left channel audio data D1L and right channel audio data D1R denoted, respectively by symbols L0, L1, L2, L3, ... and symbols R0, R1, R2, R3, ... (FIGS. 2A and 2B), are arranged in blocks at a period of 30 [msec] and then interleaved.
In the digital audio tape recorder 1, recording tracks TA and TB are divided into a scan start side area and a scan end side area, and the audio data are recorded onto each area.
FIG. 3 shows it schematically. Namely, in a first recording track TA having a positive azimuth angle, left channel's even series of audio data L0, L2, ..., L1438 are recorded onto the scan start side area, and right channel's odd series of audio data R1, R3, ..., R1439 are recorded onto the scan end side area in succession to the scan start side area.
In a second recording track TB having a negative azimuth angle, right channel's even series of audio data R0, R2, ..., R1438 are recorded onto the scan start side area, and left channel's odd series of audio data L1, L3, ..., L1439 are recorded onto the scan end side area in succession to the scan start side area.
As has a representative of this method of interleave, for example, U.S. Pat. No. 4,685,004 is known.
When the user selects the reproducing mode in the digital audio tape recorder 1, a reproducing signal SPB provided from a magnetic head is amplified by a reproducing amplifying circuit 16, and thus output to the next 10-8 demodulating circuit 18.
The 10-8 demodulating circuit 18 converts the amplified reproducing signal into a two-value signal, and then 10-8 demodulates the two-value signal, contrary to the manner of the 8-10 modulating circuit 12, and operates to reproduce audio data, an error correcting code, sub-data, and the like.
A digital signal processing circuit 20 error corrects the output signal of the 10-8 demodulating circuit 18 by using the error correcting code, and interpolates the resulting audio data as required.
The digital signal processing circuit 20 de-interleaves the audio data sequentially output, to reproduce digital audio signal D2.
Audio instruments used in a studio or the like are designed to record and reproduce a long bit-length digital audio signal, compared with a digital audio tape recorder for consumers.
If a long bit-length digital audio signal can be recorded and reproduced by the digital audio tape recorder, a digital audio tape recorder with higher sound quality can be realized.